The present invention is directed, in general, to wireless communications networks and, more specifically, to a time division multiple access system capable of providing multiple single-phase access.
The field of wireless communications encompass a variety of products, including personal devices such as pagers, cellular phones, and PCS phones, and information systems, such as wireless LANs (local area networks) and smaller wireless office networks. These products are widely used due to their convenience and comparatively low cost. This widespread usage has greatly burdened the available RF bandwidth used by these devices.
To maximize usage of the available bandwidth, a number of multiple access technologies have been implemented to allow more than one subscriber to communicate simultaneously with each base transceiver station (BTS) in a wireless system. These multiple access technologies include time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA). These technologies assign each system subscriber to a specific traffic channel that transmits and receives subscriber voice/data signals via a selected time slot, a selected frequency, a selected unique code, or a combination thereof.
TDMA technology is used in wireless computer networks, paging (or wireless messaging) systems, and cellular telephony. In a TDMA protocol, each device (e.g., pager, cell phone, laptop PC) receives and/or transmits data in an assigned channel that corresponds to a specific time slot (or phase) in a specific frequency bandwidth (typically 30 KHz wide).
Additionally, addresses may be used within each channel to distinguish between users and to increase thereby the number of users that a TDMA wireless network may serve at one time. This is particularly true in paging systems and wireless LANs, where a mobile unit (e.g., pager or laptop PC) does not continually receive data traffic from a network BTS, but rather receives data traffic in large bursts that are separated by periods of inactivity. Thus, for example, a pager having address xe2x80x9c7xe2x80x9d will only respond to data if the data is received in the correct frequency bandwidth and in the correct phase (time slot), and if the data has the correct address (i.e., xe2x80x9c7xe2x80x9d) in the header.
Within a selected frequency bandwidth, a TDMA user device may be assigned to receive data sent to the correct address in one fixed phase/time slot. This operating mode is sometimes referred to as xe2x80x9csingle phasexe2x80x9d operation. For example, if the pager or computer used by User A is operating in single-phase mode, the device may receive only data that is sent to Address 4 in Phase 1 of Frequency Band X.
Alternatively, a TDMA user device may be assigned to receive data sent to the correct address in one phase/time slot that may vary. This operating mode is sometimes referred to as xe2x80x9cany phasexe2x80x9d operation. For example, if the pager or computer used by User A is operating in any-phase mode, the device may receive data sent to Address 4 in Phase 1 of Frequency Band X at one point in time, but at another point in time may receive data sent to Address 4 in Phase 2 of the same Frequency Band X. In this manner, if a large number of user addresses are added to the wireless network in Phase 1, the wireless network can use the any-phase mode to send data to User A in Phase 2.
Finally, a TDMA user device may be assigned to receive data sent to the correct address in all of the phases/time slots. This operating mode is sometimes referred to as xe2x80x9call phasexe2x80x9d operation. For example, if the pager or computer used by User A is operating in all-phase mode, the device receives all data sent to Address 4 in Phases 1, 2 and 3 of Frequency Band X. This mode allows a large amount of data to be sent in a relatively short period of time to a single device, by is rarely used because it limits the number of users that may access the wireless network.
The prior art systems do not provide sufficient flexibility to allow a wireless mobile unit to receive data in more than one phase, but less than all of the phases, as in the case of all-phase mode. Typically, if a BTS sends data in more than one phase to a mobile device, the mobile device defaults to an all-phase mode of operation. This causes the mobile device to receive and to process data in every phase, including phases that do not contain data intended for the mobile device.
Furthermore, the prior art systems do not provide sufficient flexibility to allow a wireless mobile unit to receive data sent to different addresses in multiple phases. The address of a mobile unit in the prior art systems is always the same in each phase, whether the mobile unit is operating in single phase mode, any phase mode, or all phase mode.
There is therefore a need in the art for wireless networks and wireless devices that allow the wireless device to receive data in more than one phase, but less than all of the phases, as in the case of all-phase mode. There is a further need in the art for wireless networks and wireless devices that allow the wireless device to receive data sent to different addresses in multiple phases.
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide, for use in a TDMA wireless communications network, a communications device that is capable of receiving data from a base station in a variable number of up to N phases, including one phase (single phase mode), N phases (all phase mode), and M phases (multi-phase mode), where M is less than N. The present invention implements the multi-phase mode of operation by capturing data from all phases (as in all phase mode) and discarding data from all phases except selected phases that are assigned to the wireless communications device. Furthermore, the wireless communications device can also be assigned different network addresses within each assigned phase, and both the assigned phase(s) and the assigned network address9es) can be modified xe2x80x9con-the-flyxe2x80x9d by the base station during routine operations.
Accordingly, in one embodiment of the present invention, there is provided, for use in a time division multiple access (TDMA) wireless network, a wireless communications device comprising 1) a receiver capable of receiving a TDMA signal transmitted from a base station in the wireless network, the TDMA signal comprising a plurality of user data streams arranged in N phases; and 2) a data controller capable of processing the user data streams in a multiphase mode, the multi-phase mode enabling the data controller to retrieve from M selected ones of the N phases of the TDMA signal at least one user data stream directed to the wireless communications device, where M may be greater than 1 and is less than N.
In another embodiment of the present invention, the data controller retrieves user data streams from all N phases and processes only data retrieved from the M selected phases.
In still another embodiment of the present invention, a value of M is modifiable.
In yet another embodiment of the present invention, the value of M is modified by the base station.
In a further embodiment of the present invention, the data controller determines a transmitted user address associated with the at least one retrieved user data stream and processes the at least one retrieved user data stream if the transmitted user address is the same as an assigned user address associated with the wireless communications device.
In a yet further embodiment of the present invention, the assigned user address is modifiable by the base station.
In a still further embodiment of the present invention, the data controller determines a first transmitted user address associated with a first one of the at least one retrieved user data stream and a second transmitted user address associated with a second one of the at least one retrieved user data stream and processes the first and second retrieved user data streams if the first and second transmitted user addresses are the same as a first assigned user address and a second assigned user address associated with the wireless communications device.
In yet another embodiment of the present invention, the first assigned user address is different than the second assigned user address.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
Before undertaking the DETAILED DESCRIPTION, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms xe2x80x9cincludexe2x80x9d and xe2x80x9ccomprise,xe2x80x9d as well as derivatives thereof, mean inclusion without limitation; the term xe2x80x9cor,xe2x80x9d is inclusive, meaning and/or; the phrases xe2x80x9cassociated withxe2x80x9d and xe2x80x9cassociated therewith,xe2x80x9d as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term xe2x80x9ccontrollerxe2x80x9d means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.